Method and apparatus for the complete dehydration of molasses



March 1, 1955 G. w. RAPPLEYl-:A 2,703,139

METHOD AND APPARATUS FOR THE COMPLETE DEHYDRATION OF MOLASSES Filed oct. 10, 195o www) MNO

United States Patent() M METHOD AND APPARATUS FOR THE COMPLETE DEHYDRATION OF MOLASSES George W. Rappleyea, Southport, N. C.

Application October 10, 1950, Serial No. 189,335

2 Claims. (Cl. 159-4) This invention relates to the complete dehydration of molasses, both the method and apparatus.

One of the objects of the invention is the provision of a method of and apparatus for producing powdered molasses which assures uniformity in the reactions of the process and in the product. This connotes the maintenance of unvarying low humidity in the medium, (air) which contacts the molasses particles in moisture absorbing relation.

Another object of the invention is the provision ot a dehydrating chamber into the upper part of which molasses in finely atomized form is sprayed under pressure in a downward direction in the form of a conical jet through an atmosphere of dry, heated air until substantially dried, the conical jet being so ordered and controlled that its diameter in the zone in which it has become dried is less than that of the dehydrating chamber, assuring that during the drying process, no incompletely dried molasses particles will contact the walls of the spray chamber.

Another object of the invention is to provide for the passage of the heat-dried molasses particles successively through the heated atmosphere within the spray chamber into an atmosphere of cold air, for hardening the dried particles of molasses in order to reduce as much as possible the tendency of the particles to stick together.

Still another object of the invention is the provision of apparatus as described, including means for causing the heated air within the spray chamber to function actively in irnpinging all parts of the conical jet of atomized molasses particles, not only to thoroughly intermingle j 2,703,139 Patented Mar. 1, 1955 Said louvers are provided respectively at their upper and lower edges with the baflles 12 and 13, which together form a nozzle for each louver which can control the volume as well as the direction of the jet issuing from the louver.

Atmospheric air enters the apparatus by way of a conduit 14, first through an air lter 15, and then a dehumidifier 16. A portion of the air entering the dehumidifier is drawn through the conduit 17 by means of the fan 18. This portion becomes the dry and heated air supply v by commingling with the combustion products issuing with the particles of the jet throughout its traverse of i oughly homogenized mass, to render all of the particles of uniform composition and density so that all will dry at the same instant and the level at which they dry can be accurately determined.

Other objects of the invention will appear as the following description of an exemplary embodiment thereof proceeds.

In the drawing, the sole figure is a longitudinal vertical section, largely diagrammatic, of apparatus embodying the principles of the invention.

Referring now to the details of the disclosure, the numeral 1 in general represents a spray chamber which is preferably a cylindrical shell 2 having a downwardly convergent conical end 3, with a discharge valve 4 at the bottom. The spray chamber is shown closed by a cover 5, having the manhole 6.

Inside there is a downwardly aring hood of frustoconical form secured at its smaller end to the cover 5, and at its larger end circumferentially to the sides of the spray chamber. The manhole 6 gives access to the interior of the hood. Said hood is coaxial with the spray chamber and a Coaxial pipe 8 carries a specially designed nozzle 9 for admitting the minutely atomized molasses to the spray chamber.

The hood 7 defines, together with the contiguous portions of the side wall and cover, an annular heated-air plenum 10. The hood 7 is provided with annular series tion between the plenum 10 and the interior of the hood.

from the nozzle 19 of the oil burner 20, within the pipe 21. Said pipe supplies the dried and heated air to the plenum 10, from which it issues as jets through the louvers 11. The major force which impels the air which issues through the louvers 11 is neither convection in the pipe 21 nor the pressure of the fan 18, although these may help materially, but the pull of the exhaust fan 22. A damper 23 in the conduit 17 may be manipulated to control the volume of air supplied to the plenum.

In the event that the use to which the powdered molasses may be put proscribes the contamination of the heated air by the combustion products of the oil burner, the arrangement may be modified to the extent that the oil burner heats the air column in the pipe 21 indirectly.

The molasses is kept in bulk in a large storage tank represented at 24, from which it is pumped-as required into asupply tank 25, where its viscosity is thinned by heating it in any suitable manner such as by an electric heater. The pipe 8 which supplies molasses to the nozzle 9 dips below the body of heated molasses in the supply tank 25. A homogenizer 26 is in a by-pass connection between the lower portion of the supply tank and the pipe 8. The homogenizer is of conventional construction, its object being to agitate the molasses at extremely high speed in order to subdivide the molasses into particles of uniform small size, which may be counted upon to dry in equal times, and therefore, to become dried at a denite point in the descent of the particles through the heated air zone of the spray chamber. There is a twoway valve 28 controlling the by-pass. ln the drawing it is turned so as to place the by-pass in communication with the nozzle 9. A high pressure pump 29 picksfup the homogenized molasses from the homogenizer 26 and delivers it at high pressure to the nozzle 9. The order of pressure may be 2500 pounds. The nozzle 9 is designed to throw out and in a downward direction, a jet of nely atomized molasses particles, the neness of the atomization being effected by the pre-homogenization of the molasses and the high pressure with which it is supplied to the nozzle 9., The heated zone of the spray chamber may be considered to extend from the level of the cover to the upper level of the cold air conduit 30, represented by the broken line. The temperature of the heated air, its volume, and ,its velocity, as well asithe manner in which it impinges upon the conical vjet of atomized particles is so correlated as to determine that the atomized molasses particles shall become thoroughly dried before they have descended` through the heated zone to the levelof the said broken line. The design of theV nozzle 9 is such that the diameter of the conical jet of molasses particles at a point adjacent the` lower end of the heated zone is less than the diameter of the shell 2, so that practically none of the molasses particles will come in contact with the surfacek of the shell 2 during the drying process. Such contact of incompletely dried molasses against the shell 2 would cause adherence of the molasses to said shell, and in time build up a layer of molasses which would necessitate closing down the plant in order to eiect its removal.

Referring to the louvers 12 and 13, it is readily appreciated that the direction of impingement of the jets of heated airA issuing from `the louvers 11 against the cone of atomized molasses particles is the resultant ofthe positions of the baies 12 and 13. In the igure, by way of illustration, the battles are `shown in varying relative positions. The baffles in the louvers at the upper level are inclined convergently downward and toward one another, reducing the volume of heated air admitted through the louvers 11, and directing such air as does enter, ina

downward direction. To be specific, the direction of the jet is parallel to the bisector ofthe angle formed by the intersection of the planes of the surfaces of the two baflles. The baffles at the lowermost level are shown divergently related, thereby admitting the maximum volume of gas. While the baffles may be adjusted in any suitable manner, any specic means of adjustment is not within the purview of this invention, it being contemplated herein that the adjustment will be manually made by an operator gaining access to the bafes through the manhole 6. The function of the jets issuing through the louvers 11 is to impinge against the conical jet of molasses particles in such a manner as to penetrate through the body of said jet, thereby heating all the particles equally so that they will all become dried at the same time and at the same level.

Another function of the jets issuing by way of the louvers is to maintain the conical jet of molasses particles in an orderly divergent direction of flow, keeping the particles away from the encompassing structure. The air issuing through the louvers 11 which are at the lowest level, flows down against the lower fringes of the conical jet and turn it approximately as shown away from the w all of the shell 2 until it reaches the end of the heated alr zone.

The initial heat of the air issuing from the plenum may be around 300. Since this heat is expended in evaporating moisture from the minute molasses particles, the temperature of the heated air will rapidly decrease until in the neighborhood of the cold air conduit 30; it may be 150 F.

The portion of atmospheric air that enters through the filter and dehumidier 16 which is not diverted into the conduit 17, passes through a temperature regulating zone in the conduit 14, which may contain a refrigerating coil 31 and an electric heater 32 that may be alternatively operated, for example, respectively, in the summer and winter, as the case may be, to maintain a determined constant temperature of the air supplied to the cold air conduit 30.

The conduit 14 has a damper 33 at the mouth of the cold air duct 30 for regulating the volume of cold dry air supplied to the cold air duct. Said duct is arranged in circumferential relation about the shell 2, and communicates with the interior of said shell by means of louvers 34 which open tangentially in the same direction. The force which draws the cold air into the shell 2 is derived from the exhaust fan 22. The effect of the tangential swirl of cold air urged downwardly by the suction of the fan 22 is to cause a spirally moving curtain of cold air to move down the sloping walls of the conical end 3 of the spray chamber. The dried molasses particles upon entering the cold air zone which begins at the level of the louvers 34, becomes entrained in the whirling air and thrown outwardly by centrifugal force so that each particle must pass through the cold air to reach the wall of the conical end 3. Since the diameter of the whirling vortex of air progressively decreases in a downward direction, the peripheral velocity of the air Will increase until nally a zone is reached in which the component of centrifugal force tending to make the air rise in the cone overcomes the downward pull of the fan. This zone is in the region of the inlet end 35 of the air exhaust Dipe 36. which is overlain by the hood 37. The downwardly moving air from above meets the upwardly moving air from below this zone, producing a relatively static condition of the air within said zone, so that the effect of centrifugal force becomes practically nullied, the thoroughly dried and cooled molasses particles gravitating out of the relatively static air and sliding down the sloping walls of the conical end 3 to the outlet 38 which is controlled by the discharge valve 4. The air within said zone is drawn into the exhaust pipe 36 undergoing a direction change about the lower end of the hood 37, which tends to separate any dried molasses particles from the outgoing air. The air exhausted through the pipe 36 consists of the original heated dry air which entered by way of the louvers 11, which did the major portion of the drying, and which is therefore quite humid. and includes also the cold dry air entering through the louvers 34, the chief function of which is not only to thoroughly cool and dry the molasses particles so that thev will not stick together or to the wall of the conical end 3 of the spray chamber, but also to lower the temperature of the particles below the point at which they may be regarded as dry with reference to a small inherent residual moisture content, so as to give some latitude in the handling of the dried molasses under atmospheric conditions without absorbing enough moisture to become damp.

The moist air is exhausted into the cyclone 39, in which separation of the dust from the air is carried out in conventional manner, the dust gravitating through the dust chamber 40, and being discharged from the lower end thereof while the air centrifugally clarified in the intermediate chamber 41 passes up the central stack 42 and through a scrubber 43, being discharged to atmosphere at the top of said cyclone.

Molasses in powdered form has been produced heretofore, but not in a practical manner to assure freedom from seasonal differences of atmospheric humidity, or continuous operation of the dehydrating apparatus. These two factors have militated against successful commercial manufacture of the product. The problem stems from the viscous nature of molasses, which requires that it be kept out of contact with the walls of the dehydrating chamber during the intermediate stages of dehydration, otherwise it sticks, accumulates in a cake, and requires costly shut-downs While the apparatus is being cleaned and restored to operative condition. Also, the hygroscopicity of the powdered molasses is so great as to render it impracticable to handle unless it is produced under such uniform conditions of humidity as to be uniformly dry to a point suiiciently below that at which it would begin to acquire tackiness at atmospheric temperature to permit a limited period of handling exposed to atmosphere before beginning to acquire incipient tackiness.

It will be understood by those skilled in the art that the present invention does provide the optimum conditions both as to method and apparatus for producing govdered molasses in a manner to obviate these drawac s.

While I have in the above description disclosed practical apparatus, it is to be understood that the scope of the invention is not bound by the specific apparatus disclosed.

What I claim as my invention is:

l. Method of making dehydrated powdered molasses comprising producing a continuous spray of particles of atomized molasses directed downwardly within a chamber symmetrically with respect to a vertical axis, causing said spray to traverse sequentially a heating zone, out of contact with structure throughout its range of traverse until dry, then immediately causing said spray to traverse a cooling zone, intersecting said spray by centripetally directed currents of dry heated air in said heating zone to prevent contact of said spray with structure in said heating zone, surrounding said spray by a circumferential swirl of dry relatively cold air in said cooling zone, in which swirl the spray particles are entrained and through which they pass centrifugally and are separated from the ambient air, and exhausting the air of said cross currents and swirl commonly at a point adjacent the lower limit of said cooling zone.

2. Apparatus for making dehydrated powdered molasses comprising a shell the lateral walls of which are symmetrical with respect to a vertical axis, means for discharging a spray of atomized liquid molasses downwardly and divergently within said shell from a point in the upper part thereof, the peripheral surface of said spray being parallel with said shell, nozzles opening into said shell from all sides in a zone surrounding said spray discharge means for directing jets of dehumidied hot air through and against said spray, for drying the molasses particles and so directed as to keep the spray out of contact with the lateral Walls of said shell throughout said zone to such height that the molasses is cornpletely dried within said zone, circumferentially distributed cold air nozzles opening tangentially within said shell immediately below said drying zone, for blowing cool dehuinidiiied air against the dried molasses particles for cooling them and setting then in a whirl to generate centrifugal force, said shell being downwardly tapered below the zone of said cold air nozzles, terminating in a discharge opening, and vacuum means having an induction mouth coaxial with said shell, located below the zone of said cold air nozzles and above said discharge opening for exhausting the air derived from both said heated and cold air nozzles.

(References on following page) UNITED STATES PATENTS Dick Apr. 12, 1921 Zizinia July 5, 1927 5 Uhl Nov. 18, 1930 Douthitt Oct. 27, 1931 Black et al Dec. 4, 1934 Bowen Nov. 19, 1940 Hall July 7, 1942 10 Peebles Mar. 2, 1943 6 Haugh Aug. 24, 1943 Haugh Sept. 18, 1945 Meade et a1. June 14, 1949 Kaiser Oct. 10, 1950 Hall Nov. 28, 1950 Stoneman June 5, 1951 FOREIGN PATENTS Great Britain Aug. 15, 1929 Great Britain Apr. 9, 1943 Great Britain July 27, 1949 

2. APPARATUS FOR MAKING DEHDRATED POWDERED MOLASSES COMPRISING A SHELL THE LATERAL WALLS OF WHICH ARE SYMMETRICAL WITH RESPECT TO A VERTICAL AXIS, MEANS FOR DISCHARGING A SPRAY OF ATOMIZED LIQUID MOLASSES DOWNWARDLY AND DIVERGENTLY WITHIN SAID SHELL FROM A POINT IN THE UPPER PART THEREOF, THE PERIPHERAL SURFACE OF SAID SPRAY BEING PARALLEL WITH SAID SHELL, NOZZLES OPENING INTO SAID SHELL FROM ALL SIDES IN A ZONE SURROUNDING SAID SPRAY DISCHARGE MEANS FOR DIRECTING JETS OF DEHUMIDIFIED HOT AIR THROUGH AND AGAINST SAID SPRAY, FOR DRYING THE MOLASSES PARTICLES AND SO DIRECTED AS TO KEEP THE SPRAY OUT OF CONTACT WITH THE LATERAL WALLS OF SAID SHELL THROUGHOUT SAID ZONE TO SUCH HEIGHT THAT THE MOLASSES IS COMPLETELY DRIED WITHIN SAID ZONE, CIRCUMFERENTIALLY DISTRIBUTED COLD AIR NOZZLES OPENING TANGENTIALLY WITHIN SAID SHELL IMMEDIATELY BELOW SAID DRYING ZONE, FOR BLOWING COOL DEHUMIDIFIED AIR AGAINST THE DRIED MOLASSES PARTICLES FOR COOLING THEM AND SETTING THEN IN A WHIRL TO GENERATE 